Field of the Invention
The present invention relates to an ophthalmologic imaging method and apparatus that use a fundus camera or the like, which are used for a physical examination in a group checkup or a general checkup, and to a non-transitory tangible medium therefore.
Description of the Related Art
Conventionally, a fundus examination is performed in a group checkup such as a resident checkup or a company checkup. Usually in fundus imaging in the group checkup, non-mydriatic imaging is performed, which does not need mydriatics. In the non-mydriatic imaging, an examination room is darkened, or a simple darkroom is used so that the eye to be inspected is shielded from indoor light, and thus natural mydriasis of the eye to be inspected is urged for imaging.
An ophthalmologic imaging apparatus that performs non-mydriatic fundus imaging includes an observation light source in an infrared wavelength range that usually does not cause miosis, and a visible imaging light source. In the fundus imaging, the observation light source is used for illuminating the fundus to perform positioning of the imaging apparatus, and then a focus lens is moved to focus on an image capture unit. After that, the imaging light source illuminates the fundus so that an image of the fundus is acquired. However, because observation light and imaging light have different wavelengths, if the observation and the imaging are performed by the same image capture unit, the acquired fundus image has a focus state different from that in the observation. Therefore, an ophthalmologic imaging apparatus, which uses the same image capture unit for observation and imaging, needs a unit for compensating for change of the focus state between observation and imaging caused by the wavelength difference.
As a technique for compensating for the change of the focus state caused by the wavelength difference between the observation light and the imaging light, there is known a fundus camera of Japanese Patent Application Laid-Open No. 2011-015955. The fundus camera of Japanese Patent Application Laid-Open No. 2011-015955 stores a movement amount of a focus lens corresponding to an optical path length difference caused by the wavelength difference between the observation light and the imaging light. When an imaging switch for imaging is depressed after focusing in an observation state, the focus lens is moved by the focus lens movement amount so that the imaging can be performed in an in-focus position for the imaging light.
The imaging method using the fundus camera disclosed in Japanese Patent Application Laid-Open No. 2011-015955 can perform imaging in the same focus state as the observation by moving the focus lens after depressing the imaging switch. However, because it takes time to move the focus lens after depressing the imaging switch, it takes time from the depression of the imaging switch until the imaging by emitting the imaging light. If an involuntary eye movement or a blink of the eye to be inspected occurs during the period, a focus state change or a fundus imaging failure may occur. Therefore, it is desired that the period form the depression of the imaging switch until the imaging be as short as possible.